The Qtum[pronounced Quantum] Foundation is a non-profit organization, developing an open source turing-complete blockchain stack, with the aim of driving the use of decentralized applications and smart contracts towards massive, mainstream adoption. Gathering some of the most prominent thought leaders in the space, Qtum has managed to remove industry-wide technological hurdles, which have up until now prevented blockchain technology from realizing its full potential. In contrast to most of the existing dApp platforms, the Qtum blockchain is built upon Bitcoin’s well-established UTXO transaction model and employs a Proof-of-stake consensus mechanism. These augmentations have far-reaching implications for the utility of the Qtum blockchain, like the ability to execute smart contracts from mobile devices as well as appliances connected to the Internet of Things. With this architecture, Qtum is compatible with both - Ethereum contracts and the Bitcoin ecosystem, while adding a wide range of capabilities absent from both. Following through on its vision, the Qtum foundation aims to establish an array of services, designed to bridge the still existing gap between blockchains and the business world, by allowing smart contracts to consistently adhere to changing commercial rules and conditions. Designed for real-world, plug-and-play usage, these services will also allow Qtum smart contracts to efficiently interface with real-time data inputs from stock markets, weather forecasts, news agencies, and the like.

Qtum’s Technology

Building on bitcoins reliable and proven-to-deliver blockchain, Qtum stacks its Account Abstraction Layer, allowing the UTXO-based blockchain to seamlessly interact with a modified version of the Ethereum Virtual Machine (EVM). With this innovation it is now possible to execute smart contracts and run decentralized applications, simply and securely, in environments that were previously out of reach for Ethereum, combining the endless possibilities provided by smart contracts with the stability and maturity of the bitcoin ecosystem.

Going Mobile & A Blockchain Powered Internet of Things

One of the main advantages of Bitcoin’s unspent transaction output (UTXO) model is its ability to sustain lite wallets. Lite wallets, utilizing the SPV protocol, allow users to interact with the bitcoin network without having to download and sync with the entire blockchain. This stands in stark contrast to the way the Ethereum blockchain operates. In order to engage with an Ethereum-based smart contract, one first has to download and sync the entire Ethereum blockchain, which to date weighs up to 50 GB - rendering the mobile use of decentralized applications infeasible. On Qtum’s UTXO-based blockchain however, it is now possible to execute smart contracts from lite wallets, which can easily be installed on any given mobile device, heralding an age of mobile decentralized applications. With about a half of all internet traffic to major sites being generated by mobile devices, this ability is absolutely necessary to allow for a massive, mainstream adoption of decentralized applications (DApps), smart contracts and the p2p economy enabled by them.

Lite wallet access also allows the syncing of a variety of devices and appliances to the Qtum blockchain, operating them according to pre-determent smart contracts. With this, a blockchain-secured IoT can be established, enabling a trustless, decentralized Sharing Economy. Compatibility across the board Utilizing an EVM analog, the Qtum blockchain is compatible with existing ethereum-based smart contracts. Ethereum contracts can be ported to Qtum with little to no change to their code and execute as expected. Furthermore, Qtum implements complete backwards compatibility, meaning that once a decentralized application or contract is deployed on the Qtum network, it will stay operational, even if the system is updated. With this, Qtum solves a huge problem, very well known to ethereum developers, who very often find their applications rendered useless by recurring changes to the Ethereum network.

The bitcoin-based UTXO transaction model also ensures that Qtum will be mostly compatible with the existing bitcoin ecosystem, allowing Qtum users to benefit from the industry’s top-notch innovations, fueled by hundreds of millions of dollars already invested in the space.Scalability, Speed, and Efficiency Both, The Ethereum and the Bitcoin blockchain, are based on a Proof-of-Work (PoW) consensus mechanism, which secures the blockchain by rendering attacks very costly due to artificially arduous computations, demanded from miners participating in the block-verification game. This is known to be very resource intensive, in both terms of energy consumption and time.Qtum is among the first fully decentralized and Turing-complete blockchain stacks to utilize an attractive and much more energy-efficient method to maintain coherence: the Proof-of-Stake (PoS) consensus algorithm, rendering attacks costly and inefficient, without having to waste precious computational resources and energy. Further increasing efficiency, bitcoin’s UTXO transaction model, implemented on Qtum, allows the network to process several transactions in parallel and in any given order. Unlike Ethereum’s architecture, which demands all transactions to be processed one at a time, in chronological order.

Bridging the Gap between Blockchains and the Business World

To bridge the gap between legacy business sectors and the blockchain space, Qtum introduces the Master Contract concept. Master Contracts allow DApps and smart contracts to trigger real-world, off-chain data inputs, auditable by a verified Oracle or the contracts mediator - while the contract’s essential elements, such as participants and authorization structures, are secured on the blockchain itself.

This allows blockchain-based commerce to adhere to changing commercial rules and conditions, while interfacing with real-time data inputs from stock markets, weather forecasts, news agencies, etc.. Cooperating with a series of partners and third parties, Qtum aims to establish a smart contract hub, offering secure and thoroughly tested contract templates, tailor fitted for a multitude of industries and use cases, such as supply chain management, telecommunications, IoT, social networking, and more. With this, it will be easier than ever for established sectors and legacy institutions to interface with blockchain technology and enjoy their benefits.

The Qtum Foundation for Open-Source Governance

The development and maintenance of the Qtum Blockchain, as well as all services provided by Qtum, are directed and supervised by the Qtum Foundation - a non-profit organization, representing Qtum’s stake and token holders. In order to avoid the inefficient conduct, open source and blockchain projects often suffer from, and to ensure a coherent and standardized implementation of the Qtum blockchain, the Qtum Foundation was established. The Foundation will oversee the development of the Qtum Blockchain, advocate governance transparency, and promote the safety and harmony of the open source ecosystem.

The Foundation consists of various committees, such as Executive Judgment, Code Review, Finance & HR, as well as Marketing & PR. Members of the Judgment Committee, the foundation’s highest executive authority, are elected by Qtum token holders. All other committees and vital functions are appointed by, and report to the Judgment Committee.

Meet The Team

Patrick Dai, Co-founder.Patrick is a Computer Science PhD candidate at CAS and has worked for Alibaba

Alex Dulub, DeveloperAlex has a 15 years background in software development and 3 years working on blockchain frameworks and business applications, as well as cryptographic protocols and crypto libraries. Alex is also a serial math\programming competition winner. His programming stack includes C\C++, Node.js, Angular.js, React\Redux

Amelie, DesignerAmelie is a UI designer for Qtum project. She graduated from Berlin University of the Arts with a Masters in Visual Communication Design.

Baiqiang D.Baiqiang studied physics at Peking University and has worked for several software companies including Jinshan Software and Cheetah Mobile

Caspal OuyangCaspal is an experienced web developer and has worked at Baidu. Caspal has 21 gold medals for Rubik’s cubing 1 record in Asia and 29 records in China. Caspal was ranked #1 for solving a 4×4 & 5×5 blindfolded and ranked #1 for solving a 3×3 Rubik’s cube with his feet in China.

Jordan Earls (Earlz), Co-founder and lead developerJordan is a trusted and well-known member of the cryptocurrency community and has been developing software since he was thirteen. Jordan has reviewed over 100 altcoins and identified multiple exploits in alternative cryptocurrencies.

Ibai Basabe, Ph.D, ResearcherIbai holds a PhD in Mathematics from the University of Florida with concentrations in Logic and Topology, an MS degree concentrating on data science and machine learning and an MM degree concentrating on piano performance. Ibai has been interested in Bitcoin since 2012 and has expertise in many aspects of the technology.

John Scianna, PR ManagerJohn has been following bitcoin since 2012 and a community member since 2013. John has been a miner, journalist, and has worked for several startups including CoinPip and the DC-based blockchain advocacy group, the Chamber of Digital Commerce.

Mike P, Internal ITMike is a blockchain technology developer and enthusiast, fell in love with blockchain since 2013 and has developed proof-of-concept platforms, block explorers, online wallets and one of the largest altcoin mining pools. Mike has taken part in several cryptocurrency projects since 2013.

Neil, Co-founder & Head DeveloperNeil has 20 years experience developing software and has four years experience in the blockchain space. Neil has Master’s degree in Business Administration from ISCAE, but later specialized in computer science. Neil was also a professional poker player and speaks four languages.

Roman, DeveloperStudied in Belorussian State University specializing on informatics and software development. Started working on blockchain projects in 2014 as C++ developer. Took part in numerous custom projects based on bitcoin/bitshares/ethereum.

Time Markov, DeveloperTime is C/C++/Qt/QML developer with 9+ years experience in building cross-platform applications. With about one year experience in the blockchain space. Enjoy in working with this team.

Brett F, Community Manager Brett worked as a Linux System’s administrator from 1999 – 2004 and then worked at a Linux desktop support company from 2005-2014. His blockchain experience started in mid-2013, and met most of the Qtum’s founding members in 2014. He manages the Slack, Bitcointalk, Twitter, and other social media channels. He also contributes to the PR side of the project, providing research, writing, and interviews.

Hi everyone, lead developer here. I'd like to give a brief summary of this section that was revealed, so that you don't have to read through the whole thing to figure out what we're doing. It is indeed a very rough draft also.

Basically, we're taking Bitcoin Core 0.13, integrating the Ethereum Virtual Machine, and adding an "Account Abstraction Layer" so that existing Etheruem contracts will work on Qtum with minimal changes. The exact way we are integrating the EVM is by adding new Bitcoin Script opcodes, and adding special processing conditions so that when these EVM using transactions are added to the blockchain they are executed immediately (rather than only when attempting to be spent, as is normal).

Along with this, the account abstraction layer allows for contracts to only worry about balances and sending funds. This is a bit more complicated to explain without going into a lot of technical detail, but I'll try. Normally in UTXO based coins (such as Bitcoin of course), you can't just say "I want to send 20 coins to X", you say "I want to send this 10 coin output, and this 5 coin output, and this 8 coin output to X, and also send 3 coins back to Y, which is my wallet." This is called coin-picking, and is one of the reasons that smart contract implementations on top of Bitcoin have been so difficult up to this point. A coin output must be either spent completely or not spent at all. What we've done with this account abstraction layer is make it so that smart contracts on the blockchain have something similar to a wallet. When a user (or other contract) sends coins to a contract, the code will create a standard "funding transaction", which is spendable only by the appropriate smart contract. It would be a great burden for smart contracts to have to pick their own coins (ie, having to write your own algorithm in Solidity), so we have added a consensus-critical coin picking algorithm which all contracts must use. So, for a contract to "send 5 coins to X", the miner will pick contract-owned coins (using the consensus-critical coin picking algorithm), and when it has enough inputs for the value to send, it will then construct the outputs of the transaction. In this case it would be "5 coins to X, remaining coins to sending smart contract (change output)". This transaction is then added to the current block. It's important to note that these transactions are not broadcast on the P2P network, they are only added by miners (and it is consensus-critical that they add them if they put the contract transaction in the block)

I'm sure that explanation wasn't 100% clear, but the TL;DR; of it is that we integrated the EVM onto a UTXO based blockchain, and writing contracts for this should be just as easy as Ethereum, but you get the benefits of the UTXO model. These benefits include mobile/light wallet support by SPV, a more stable model (whereas Ethereum has forked many times to fix problems with this), and compatibility with existing Bitcoin tools and protocols.

Q) I have read the qtum whitepaper over last 1 hour so understanding may not be 100% but this is my assessment. Basically it is just another bitcoin fork with extension to the bitcoin scripting language to support solidity contracts?

A) First of all, Qtum is far from being “just another bitcoin fork”. We have a vision for the Qtum project and one of the biggest and most professional teams ever seen in crypto with support from real world companies and investors. Our goals for Qtum go far beyond the crypto scene and it will be a top project, not just another fork.Our choice of bitcoin core as a main base for Qtum is based on the fact that bitcoin is the most mature, stable and secure blockchain available, in comparison to ethereum or bitshares or others which are still considered unstable with the numerous problems and security issues they had since they launched. In addition to bitcoin having the biggest support from the community which offers a large collection of tools and software related to bitcoin which can be used by quantum as well, in contrast to the other blockchains which sometimes lack even the simplest software (mobile wallets, stable desktop wallets …).Also we use bitcoin script as a bridge between the EVM and regular transaction, the Qtum model was very well designed, and is much more complicated than you make it sound.

Q) There is no compelling reason to choose UTXO over smart contract via balance. It is like comparing a general journal vs a general ledger, which is better? The answer is it depends. I guess it is only UTXO because it is using a bitcoin fork and calling it UTXO as a feature is just a gimmick. In fact i suspect scalability becomes bigger problem since you need to maintain SPV to manage UTXO for multiple different states? Will be interesting to see how to implement wallets. Does that make hyperledger better since they supports both utxo and balance?

A) Our choice of UTXO is simply choosing the best technology, there have been some efforts made through some articles to make the account model seem as performant and secure as the UTXO model, however, it’s not. Without going into much details, the account model is too naïve and simplistic and offers no parallelism, it always reminds me of the cup telephone transaction model.

For us, a hybrid model as the one used by Hyperledger was the wrong choice since it will cause us to be incompatible with neither bitcoin nor ethereum. In Qtum we have a priority to keep full compatibility with bitcoin which will allow us to implement future bitcoin BIPs to Qtum thus taking advantage of the developments done by the bitcoin core team and community.For more details, please refer below：

1) If we wanted just a simple smart contract platform to build on top of, it would've been significantly easier for us to just fork Ethereum.

2) The UTXO allows for the SPV protocol to work. Ethereum currently does not have anything like SPV. There's no way to run a simple wallet on Ethereum without downloading the entire blockchain, or trusting a centralized 3rd party.

3) The UTXO model is overall much more simple, and because it's been used by Bitcoin, it has been thoroughly tested and proven to be secure. Although Ethereum's account model is conceptually easy to understand, it requires more complexities and edge cases in order to secure it from replay and double spend attacks.

4) Scalibility should not be a problem for Qtum. Although contracts can create state changes etc, these state changes are not directly stored on the blockchain. Rather, state is considered the accumulation of all actions and differences created by executing each smart contract. This could admittingly make syncing the blockchain slower (because block processing will be slower than Bitcoin), but the other benefits provided are worth this performance hit. Furthermore, the only additional thing stored in the UTXO set right now is contract code, and contract-owned outputs (though their data becomes unimportant after the output is initially processed). There may be plans proposed later which prune the UTXO set's stored data as well, to reduce the UTXO set size further.

5) SPV will work almost identically to how SPV wallets work today. For a quick summary, a light wallet downloads block headers, and then sends P2P nodes requests (using bloom filters) to get all transactions for each block matching the keys that this wallet own. Because the contract system creates normal transactions, this already works. IF you a contract sends funds to a SPV wallet, the SPV wallet will see these funds and can spend them, today. Our next step with SPV wallets would be to implement a workflow so that people can send money to a contract, while also picking which function and what data to send. We do not need to extend the SPV model to work for Qtum, it already works because of our focus on compatibility.

6) Regarding Hyperledger. I'm no expert on it, so I could be wrong. But I think that their support could end up being worst of both worlds. Now, anything wanting to interact with Hyperledger must be capable of dealing with the quirks of both models. From my understanding also, they only support either UTXO or Accounts on one ledger at a time also (though there is much functionality for messaging and sending things between these ledgers). So I do not think it makes Hyperledger's model better, but rather more complex. Perhaps this complexity provides more power to Hyperledger's model, but it also introduces more security concerns and increases the implementation cost of Hyperledger itself, and any application that uses it (due to to having to deal with both models)

Q)It extended bitcoin script to accept solidity string but another company called CounterParty have already done it on the Bitcoin public blockchain without having to use a new public blockchain. So where is the need? Furthermore, will qtum have to constantly keep in sync with "solc" the solidity compiler to maintain compatibility?

A) Qtum is very different from XCP, XCP uses bitcoin blockchain to store data, and the user have to run XCP software on top of that. Some major drawbacks are the cost of XCP transactions which increased so much that it threatens the whole project now and the complexity to build external software on top of XCP.Qtum aims to offer an all-in-one solution, not based on any external possible points of failure.

For solc support, we made Qtum with that in mind, Qtum uses the exact same ethereum VM, so it will run any solidity compiled code, in the case of EVM updates, and we will be easily able to update it in Qtum as well.

Q)Qtum is a new altcoin platform but there are enough ethereum, ripple and bitcoin out there. Why another one? It is not a bridge as I was led to understand. It is another bitcoin fork.

A) In addition to my previous reply about Qtum not being “just another bitcoin fork”, I would like to add that quantum is not the average altcoin, it will be one of the best, if not “the best” we have all the means for that, and we will do it.

You say it is not a bridge, but really it is. It is bridging the technology. We are taking what makes Bitcoin great, and what makes Ethereum great, and bringing them together as one. We expect to bridge not the actual monetary value (ie, the market cap) held in each coin, but rather the communities and separate interest. Right now there is a real divide between serious Ethereum users and developers, and Bitcoin users and developers. By aiming to be compatible with the technology involved with both, we hope to merge these communities and be an answer both for 1) Those who want Ethereum smart contracts, but are uncomfortable with the stability of the Ethereum account model and lack of protocol support such as SPV; and 2) Those who like Bitcoin, but are unhappy with it's limitations for implementing smart contracts and more powerful types of transactions. We as a team are also tired of these copy-paste coins that people constantly make to try to get a quick buck, and we would not have chosen to make this it's own altcoin if we had not weighed the cost and benefits very carefully.

Q)What is the block confirmation time? Bitcoin is 10minutes and Ethereum is 18seconds?

A) Ethereum blocktime of 18 seconds is a bit exaggerated and causes a lot of empty blocks and uncles thus bloating the blockchain with useless data (which resulted in the currently atrophied ethereum blockchain), and bitcoin block time of 10 minutes is a bit too long for a smart contracts platform. We aim to have a block time of 1 to 3 minutes for Qtum.

Q)I did not go too deep into the details of the POS but the protocol is similar to Peercoin's DPOS and it maybe susceptible to coin age accumulation attack if the intention is to incentive to miners that leave their stake longer on the chain. In fact it should be the opposite to prevent long range attack, Bitfury and Vitalik has written good articles on the types of attacks it is susceptible to.

A) Qtum uses BC PoS v3.0 which has removed all major attack vectors, including coin age accumulation. In conclusion, Qtum will be the first standalone UTXO and PoS based smart contracts platform thus making use of the best available technologies to deliver an outstanding blockchain solution.

It has been a few days since we gave a status update, so we would like to give an overview of what’s going on behind the scenes.

Recently, we have begun work on a new website. That should be ready in about 3 weeks, until then, we will continue to use the current one (https://qtum.org). The section where we list our Angel Backers has been updated, we will reveal more names shortly once we have approval. We plan to discuss with our Angels why they decided to support our project, and what they expect from our team in the future.

The Qtum Crowd Sale will start on March 1st. We currently have enough funds to last until the sale ends on April 1st. The Crowd Sale will be hosted by major Chinese exchanges, which will be announced in February. There will also be a direct sale that is done on our website. The concrete information about the Crowd Sale will be announced in our business whitepaper prepared by PricewaterhouseCoopers. The technical whitepaper will come out mid-February. The draft section that we released a few weeks back was from the last revision of the whitepaper, so that portion will be completely redone for the new version.

On the Press front, we have done a decent job gaining traction with Blockchain industry sites. Our focus right now is engaging with the mainstream press. A large part of this project involves preparing a Blockchain project for real world business applications. We already have a signed partnership agreement with a company valued at 100 million dollars USD, which we will discuss later. We are currently in discussions with more companies, who are excited about our “Go Mobile” strategy. This was actually the portion of our project that convinced a billionaire to back Qtum.

Our development team is currently merging the Proof-of-Stake protocol into Bitcoin Core v0.13, along with some testing of the Account Abstract layer we implemented to allow the EVM to run on a UTXO model. The screenshot earlier of the mobile wallet is what you can expect to see once we have a working testnet. Jordan Earls can give a better update on this later, and it’s best to ask him questions directly if you want more details.

Again, if you would like to speak with our team directly, there is always someone on Slack:

Patrick will be speaking at the European Ethereum Development Conference, February 17th - 18th in Paris. If you are going and would like to attend his venue, please let us know: http://edcon.io

Q: What is EDCON?

A: The EDCON (European Ethereum Development Conference) is a conference that will take place in Paris at the Ecole Supérieure de Commerce de Paris - Europe (ESCP) on 17-18 February 2017. The conference will cover Ethereum technology and research (PoS, Scalability, Privacy) as well as Ethereum-based applications.

Q: Who is organizing EDCON?

A: EDCON is organized by LinkTime with the support and cooperation of developers from the Ethereum Foundation and the wider Ethereum community, as well as ADETIF, the Ecole Supérieure de Commerce de Paris - Europe (ESCP), the Asseth (French Ethereum, nonprofit), La ChainTech (French blockchain, nonprofit).

Standard Ticket: Able to attend the Main Conferences, morning community event and activities of Ethereum Community in Subconference.

VIP Ticket: 100 Tickets only. Able to attend the Main Conferences, Cocktail Party and activities of Ethereum Community in Sub-conference. VIPs are able to build deeper connections with core developers, investors and entrepreneurs. Highly recommended for those who want communicate more with core participants.

Qtum Q&A session with Patrick Dai, Jordan Earlz, and guest Bo Shen took place yesterday. Posted below is a very long list of questions responded to. Please keep in mind, this list is just responses from the team. There are over 600 people on Qtum Slack currently, and there were quite a few active participants, so for these images some of the extra talking was edited out. A full transcript will be provided later on the Qtum website but if you would like to read it in full, you can join the Qtum Slack.